Improvement in machines for threading wood-screws



N. FEIERS, PbiOTO-LITMOGRPHER, WASHINGTON. n. CA

UNITED STATES PATnigT QFFICE.

Il. A. HARVEY, OF NEW YORK, N. Y.

IMPROVEMENT IN MACHINES FOR THREADING WOOD-SCREWS.

Specification forming part of Letters Patent No. 42,766, dated May 17, 1864.

- To all whom it may concern:

Be it known that I, H. A. HARVEY, of the city, county and State of New Yorlghave invented certain new and useful machinery for cutting threads upon wood and other Screws, including apparatus for delivering blanks one by one to the machine, said delivering apparatus being also applicable for other purposes 5 and I do hereby decla-re that the following, taken in connect-ion with the drawings, is a full, clear, and exact description thereof.

In the drawings, Figure l is a plain or top view of the whole contrivance. Fig. 2 is a front elevation thereof; Fig 3, a rear elevation thereof; Fig. 4, a vertical section through the same on the line xx of Fig. l. Fig. 5 is a rear elevation in detail of certain parts. Fig. 6 is an end elevation of the inclined plane that gives the pitch to the thread and its actuating cam and cog. Fig. 7 is au end elevation of the mechanism that gives to the tool-holder its motions toward and, from the blank. Fig. 8 is aplan ofthe mold or pattern which causes the cutter to give form to the screw; and Fig. 9 is an end elevation eX- planatory ot' the gearing, giving motion to the various parts of the machine.

This machine is intended to act upon blanks that have already been nicked and shaved; and it consists, mainly, of a series of sliding and rotating receivers and holders acting in com; bination with ascrew-driver to revolve the blanks, and a tool which has imparted .to it the' proper motions to cut the threads thereon.

In connection with the machine is an apparatus which delivers to it the blanks singly and in succession as the exigencics of the machine require.

The @hole contrvance is mounted upon a strong frame, a a a, in the two sides of which are formed guiding-slots b b, in which slide two boxes, c c, in which, upon a proper shaft, is mounted a wheel, d d. This wheel is a starwheel, and each of its points is turned off so as to form a short cylinder, as at d d. Each cylinder is pierced with a cylindrical hole of suiiicient size just to receive the body or barrel of a screw-blank. The bore may be slightly enlarged at the end, as shown in the drawings, (see specially Fig. 4,) so that blanks may be inserted more readily. Between the adjustingscrews.

cylinders and the center of the wheel pieces of steel, d2 d2, are screwed fast to the arms of the star, and these pieces are at the ends near the cylinders so bored through as to iit accurately the under side of the head and a small part of the body of a screw blank, and that part of the pieces d2 farther toward the center of the wheel contains a cavity, d3, Fig. 4, which incloses ,about one-half of the body of a blank, supposing it to be divided lengthwise. A screw-blank will, therefore, rest in one of the pieces, d2, with the lower side of its head and a part of the body nearest thereto wholly inclosed, and with one half of the rest of the body inclosed and the other half exposed. (See d4, Fgs. 2 and 4.) The whole cavity, including the cylindrical bore large enough to admit the head, the concial bore, which receives and supports the head, the smaller cylindrical cavity, which just contains a portion of the barrel, and the semicylindrieal or nearly semcylindrical cavity, which incloses one half, or thereabout, of the rest ofthe barrel, constitutes a receiver'and holder, and a series of them must, in my machine, be so mounted that they will both revolve and slide; but the precise number of receivers, or the precise manner in which the cavities are made, or the number of pieces of which they are constructed, or by what precise apparatus the series is caused to revolve and slide, is immaterial. A forked slide, e, is attached to or made in one piece with theboXes c c, and is guided by proper slots in the trame. From this slide depends a pin, e', and the pin enters a cam-groove, e2, in ar revolving cam-Whee1,f. Upon the starwheel are a series of pins, g g g, and an impelling-pawl, g', is hinged to a piece, g2, which is attached to the frame by This pawl is pressed down by a spring, and prevented from fall-ing too far by a projection, g4, which always rests on one or other of the pins. A springholding pawl, g3, is bolted to the slide and has at its end a cavity fitting and capable of receiving about onehalf of one of the pins. A socket, h, bored out so as to receive with a close tit the outer ends of the receivers and carriers, is secured tothe bedfplate in such position as to inclose the end of one of the carriers when the carrying-wheel is advanced; and a screwdriver stock, t', having on itsend a screw-driver, lies within the socket, so supported that its aXis is coincident with the axis of the socket. This stock is prevented from moving endwise by collars or shoulders on the shaft i', to wht-h it is secured, and is kept in revolution continually during the action of the machine by means of a cog-wheel, i2, secured upon the shaft that carries the stock.

The action of these parts is as follows: Supgroove c2 which leads awa from the socket vrthen the groove commences to draw the slide, and consequently the star-wheel and the receiver, within the socket away from the. latter. The star-wheel is thus slid backward until the receiver within the socket is fairly out of it. At orjust after that time one of the pins r/ onthe wheel is brought in contact with the impelling-pawl, and as the wheel slides back it revolves until the next carrier in succession comes in line with the socket. At that time the holding-pawl, by means of its spring, embraces one of the pins, holds the star-wheel `in the position to which it has been revolved, and the pin e is at the apex of the cam groove. IA further revolution of the cam causes the star-wheel to advanre rapidly without revolution until the carrier in line with the socket enters it to some distance. The advance is then made more slowly and becomes slower and slower (seev shape of cam from a to y) until the carrier is pushed home into the socket with the screw-driver inserted in the nick of a blank. By this slow motion of a carrier I am enabled to enter a revolving screw-driver into the nick of a blank with certaintyand without any danger of marring the head, as I have ascertained by actual trial, and the fast motion of the carrier up to the time that the head of the blank is about in contact with the end of the screw-driver enables me to save time in-the working of the machine. As soon as the receiver is pushed home all motions of the star-wheel cease. The pin now'being in that part of the cam-groove which is straight, the blank commences to revolve as soon as its nick is fairly entered by the screwdriver. A sliding shaft, j, whose axis is parallel with that of the blank being revolved, is secured in the machine. Itis forced in one direction by a spring7", and in the other by an inclined plane, jz, which is mounted upon a slide, js, which is moved upward by a cam, ji, and downward by itsY own weight or a spring. Both the slide js and the sliding shaft should be so held by guides or feathers or similar contrivanccs that they may slide endwise and cannot revolve, and rollers may be applied between their ends and the cam and inclined plane. The tool post or holder r is mounted on the shaftj in s ich wise as to be free to oscillate therron, but to he forced to follow the endwise motions of the shaft. This post carries at its upper ynl a threading or chasing tool of any usual or proper construction and is prolonged downward until it enters a slot or cavity, k2, (see specially Figs. 7 and8,) in apiece of metal, le. One side ot' this cavity constitutes the mold or former. The lower end of the tool-post has attached to it a spi-ral spring, k3, which always tends to draw the tool away from the screw-blank. The mold is secured to a rock-shaft arm, in, fastened upon a rock-sl1aft,m, which carries at its other end another arm, m2. This latter arm has I upon it a pin that enters a cam-groove, m, on the end of the cam-wheel f. This groove, when in revolution, oscillates the rock-shaft, and consequently the mold and tool post and tool. The action of these parts is as follows: Supposing the operation to commence at the time when a receiver is home in the socket and the blank is revolving. At that time the inclined planeis down. The sliding shaftis shoved endwise toward the socket, and the cam-pin attached to m2 is in such position as to permit the spring 7c3 to hold the tool out of'contact with the blank. As the inclined plane com mences to rise it moves the shaft endwise and at the same time the cam-groove m3, acting through the agency of the mold, forces the chaser against the blank far enough to make the irst cut', and there holds the chaser, which, by the action of the inclined plane, is forced along the screw so as to give the pitch, and has at the same time its depth of cut modied by the sliding of one end of the tool-post along the mold. As soon as one cut is nished the cam m3 permits the spring k3 to draw the tool away from the blank, and as soon as it is so drawn away the cam j4 permits the inclined plane to drop and the spring j moves its shaft endwise, in consequence of which the chaser returns to its commencing-point out of contact with the blank. When there, the cam m3 brings it up to its work again, but with a deeper cut, and the inclined plane raised by its cam ji again gives it the same pitch. When this cutis finished, the tool again returns as before, and thus as many cuts, each deeper than the last, are given as may be necessary. When the last cut is done, the cutter is again released and thrown forward and again is traveled along by the pitch plane; but durin g this travel the cam m3 holds it entirely out of contact with the blank, or rather the screw, for it is now nished, and while the cutter is thus moving out of contact with the screw the starwheel slides back, turns, and slides forward, removing the finishedV screw and carrying a new blank to be revolved by the screw-driver and chased by the cutter, which commences to act again when the new blank is revolving and its receiver and carrier is fairly home in the socket.

Those acquainted with the art of making screws by machinery will know how to lay out the cam to give as many cuts as necessary, and how much each cut should increase in del th, and also how to time the revolutions ot' this cam with those ofthe cam that moves the wedge or pitch-plane and with the screwdriver shaft, and revolutions may be imparted to both cams and the screw-driver by any proper train of gearing. I have indicated in the drawings proper gearing for the purpose, and consider further description unnecessary. Duringv these operations I have supposed the blanks to be put into the receivers by hand, and it is evident that the finished screws will drop outas the star-wheel revolves. And the otjces ot' the receivers and carriers are as follows: First, to receive the blanks; second, to carry them to the place where they are to be threaded 5 and, third, to hold them there so that they may be revolved by a screw-driver and chased by a chasing or threading tool, and they must be so constructed, substantially as described, as to be able to perform these duties. The office of the socketis to hold one of the receivers Iirml y in place, so that the blank it contains may be properly revolved and threaded. The pitchplane gives the vpitch or lead to the screwthread, andthe mold gives shape or contour to the screw, while the cam m3 brings up the tool, holds it to its work, and permits it to be withdrawn at the proper time.

I have already stated that blanks may be put into thereceivers by hand. 'lhey may also be inserted by any of the feeders applicable to the purpose and known to manufacturers of wood-screws; but I prefer to deliver the blanks to the receivers by an apparatus of my own invention, now to be described.

The delivery apparatus consists of an ordinary inclined conductor, bent or curved near its end, in which slides a gate that permits the blanks to drop, or shoves them out one by one from the end of a column and holds back the column until it becomes requisite to drop the next blank in succession.

In the drawings an inclined way or conductor, which is composed ot' two pieces with just space enough between them to receive a screw-blank and permit it to slide, is shown at 0 o o o. This way is, as I prefer, bent at right angles, and its two sides are beveled at top s) as to ft the lower side of the blanlzheads. `J ust at the bend one of the sides is cut away and a slide, p, is so fitted as to play in the lower part of the way. When this slide is retracted, (see Fig. 4,) the column ot' sci ews which is fed into the ways by hand or by machinery rests against the bent part ot' t ie conductor. When the slide advances, (see red lines, Fig. 2,) it pushes out the blank which lies in front of it, and at the same time stops the further descent of the column, and the blank thus pushedIout descends as it advances, owing to its head sliding down the ways, and nally drops 0E the end of the ways. In

order to prevent the blow of the slide from throwing the blank out too tast when the machine is working at speed, I attach to the slide a hook, p', which prevents the blank from advancing faster than the hook nimes. In the drawings the slide is shown as mounted on a standard and has attached to it a rod which enters a case or socket in which is contained a spring so contrived and attached that it always tends to dra-w the slide backward, and to the slide is also attached a swinging rod, 1^, with a hook or latch upon it, and this rod is forced toward the star-wheel by a spring, 1. Upon the frame of the machine is mounted an unlateher or disconneetor, s, and the operation of all theseparts is as follows: When the star-wheel moves back, one of its arms strikes the curved end of the swinging rod and the latch and forces it away from the wheel. When the wheel has been moved back and is revolved, one of the receivers and carriers lies directly under the blank that lies in front of the slide and rests against the bent part of the conductor, and the latch lies against that side of one of the arms which is nearest to the sockets. As the carrying-wheel is advanced it carries the latch, and consequently the slide and the blank in front of it, forward just as fast as the receiver under the blank advances, and the blank slides or is pushed gradually down the ways into the receiver. (See red lines, Fig. 2.) When the receiver has passed beyond the ways, the curved part of the swinging rod strikes the unlatcher which frees the latch from the arm and the spring in the case q draws the slide back,

permitting the column of screws to drop, and all parts of the delivering mechanism remain in this position until another blank isneeded. If the operation ot' these parts be studied, it will be seen that the blanks hang by their heads, points down, and the receiver co-operates with the slide and waysin delivering the blank, which falls point first, and that there is little, or I may say, no chance of a failure of delivery. It will also be seen that if a conical tube, with thelarge end up, were fitted below the lower and bent part of the guides that my deliveryin g apparatus would then be capable of delivering blanks into a receiver which did not move with the blank. It will be seen, further, that the upper end of the ways might be horizontal provided the column of blanks were fed along by a pusher actuated at intervals by the machine, and also that the lower end ot' the ways might be curved provided the slide moved in the curve of the lower part of the ways; and I intend at times to make the bend in the ways at other angles than at right angle and to deliver each blank to the receiver at the time when the rotation ot' thestar-wheel is taking place.

When I claim the delivering apparatus in combination with a receiver that moves as the slide moves, I do not mean a receiver having all the characteristics of the receiver herein described, but intend the claim to apply to any receiver capable of holding;` and transferring n serew-hlnnk in the operations of Wood-screw machinery.

l claim us ot lnv onn invention.

1. .The combination ofa series of sliding and rotntingreccivers and lloldershavingthe characteristics substantially as speoited, with a socket; and a revolving` so: eW-driver. the parts operating in combination as described.

2. ln combination with u revolving screwdriver, 'fi receiver and carrier, or a, series thereof, movtd toward the screw-driver by 2L diiierentiul or fust-and-slow motion, substanti-llly in the manner and for the purpose speci fied.

3. Afdelivering apparatus consisting of a bent or curved inclined wavy and a slide operating in the lower or bent end thereof, the whole having L mode of operation substantially as described.

4. In combination with a delivering appa,- ratus substantially such as described, a receiver and carrier which moves as the slide of the delivery apparatus moves, so that the blank may be delivered and received under a mode of operation substantially as set forth.

H. A. HARVEY.

In presence of- J As. S. WIGHTMAN, 1*. JAMES GAGE. 

